a. Field
Methods and compositions for increasing the solubility of alloxazines in a solution, as well as inactivating pathogens in biological fluids, are provided. A new form of riboflavin with increased solubility is also provided.
b. Related Art
Contamination of whole blood or blood products with infectious microorganisms such as HIV, hepatitis and other viruses as well as bacteria present a serious health hazard for those who must receive transfusions of whole blood or administration of various blood products or blood components. Such blood components include red blood cells, blood plasma, Factor VIII, plasminogen, fibronectin, anti-thrombin III, cryoprecipitate, human plasma protein fraction, albumin, immune serum globulin, prothrombin complex, plasma growth hormones, and other components isolated from blood.
One solution for providing safe blood or blood products to a recipient is to screen the blood or blood product (herein the terms “blood” and “blood product” are used interchangeably) for contaminates prior to using the material in a patient. When a blood product tests positive for a particular pathogen, the blood product is removed from circulation and destroyed. However, blood screening procedures may fail to detect pathogenic contaminates due to inadequate specificity or sensitivity, for example, a blood product is screened for the presence of hepatitis C, when the blood is infected with West Nile Virus, or the blood product is screened for hepatitis C but the virus is present in an amount below the detection sensitivity of the particular screening methodology. In these situations, the blood screener will leave the blood in circulation noting that it does not contain a detectable level of hepatitis C contamination, where in reality the blood product really has West Nile Virus contamination or a level of hepatitis C contamination that will still damage the health of the recipient.
A second solution for providing a safe blood product to a recipient is to “sterilize” the material prior to use in the recipient. One particularly useful blood product “sterilization” method is to add at least one photosensitizer directly to the blood product. Some types of photosensitizers have a high affinity for nucleic acid. Typically, nucleic acid in a blood product is associated with pathogen presence, allowing the photosensitizer to be preferentially targeted to the pathogen within the blood product. Blood product is then irradiated at an appropriate wavelength, for the photosensitizer, for transfer of the absorbed energy from the photosensitizer to an energy acceptor, i.e., the energy is transferred to the pathogen's nucleic acid. Essentially all pathogens within a blood product be destroyed using this treatment, otherwise, a recipient will receive contaminated blood and be at risk of being infected by the particular pathogen. The amount or level of photosensitizer available within the blood product is a significant aspect of ensuring destruction of pathogens in a sample.
The usefulness of photosensitizer driven destruction of microorganisms is based partly on the amount or concentration of photosensitizer in effective contact with the microorganism, and partly on the “light dose” that reaches those photosensitizers in order to activate the compound and cause killing of the microorganism. In general, the light dose is maximized in order to activate the photosensitizer, but not cause damage to the surrounding blood or fluid products, i.e., erythrocytes, platelets, etc.
However, providing a sufficient amount of photosensitizer to a blood product so as to provide effective killing or inactivation of pathogens in a defined volume of material has proven difficult. In particular, the solubility (measured by its Ksp) of different photosensitizers has limited the amount of photosensitizer that can be added to a blood product. In preparing a photosensitizer for use in a blood product, the solid photosensitizer must first be combined with a solvent to put the material into solution, and then the solution is added to the product at a ratio that does not adversely affect the osmolality of the blood product. This has conventionally provided the limit on how much photosensitizer can be added to a blood product during a “sterilization” treatment.
Dilute quantities of photosensitizers can result in potentially inefficient killing and treatment of pathogens. Therefore, it would be beneficial in the sterilization treatment of blood product to have highly concentrated photosensitizer solutions that are added to the blood product in small amounts and yet provide adequate levels of photosensitizer to the sample to ensure pathogen inactivation. Further, new photosensitizers and forms of photosensitizers are sought after to provide additional tools in the treatment of blood products. New photosensitizers and forms thereof can provide improved energy transfer from the new compound to the blood born pathogen as well as modified solubility characteristics for inclusion with the blood products.
The disclosure has been developed against this backdrop.